Back blade assembly and control therefor



United States Patent {72] Inventor Edward J. Jackoboice Grand Rapids, Mich.

[21] Appl. No. 679,864

[22] Filed Nov. 1,1967

[45] Patented Dec. 15, 1970 [73] Assignee Monarch Road Machinery Company Grand Rapids, Mich.

[ 54] BACK BLADE ASSEMBLY AND CONTROL Primary Examiner-Robert E. Pulfrey Assistant EmminerAlan E. Kopecki Attorney-Price, Heneveld, Huizenga and Cooper ABSTRACT: This disclosure relates to a back blade assembly and a control system therefor. The blade is attached to the back of a vehicle through a rigid support which can be H- shaped, for example. This support is rotatably attached to the truck and to the blade so that the blade can be raised and lowered. A second support means is rotatably attached to the rigid support but reciprocatable at the attachment through this support and is rotatably attached to the blade below the attachment of the first support. Power means, such as .a hydraulic cylinder are provided to raise and lower the blade. A hydraulic cylinder control system is provided to raise and lower the blade. The control system employs a modified fourway valve which actuates the raising and lowering of the blade and also has a means to maintain a predetermined pressure on the blade less than that pressure supplied when raising the blade.

This'invention relates to a back bladejassernbly and 'a control system therefor. In one of its aspects-it relates to a back" blade assembly for a truck and the like comprising a first sup port meansadapted to be rotatably attached to the back portion of the truck, the support means being rotatably attached to the blade, a second support means rotatably attached to the blade a spaced vertical distance from the point of attachment of said first support means, said second support means being' rotatably. and reciprocatably'attached to said rigid support and lower said blade when attached to asupport.

In another of its'aspects', .the invention relates to a control system for a scraping blade assemblyco'mprising a'fluid supply means, a pressure supply means, ahydraulic cylinder havinga piston at an inlet means at two ends of said hydraulic cylinder, a valve controlling the fluid supplied to either side of said cylinder to move'said piston; said valve having means to maintain a piston in one position with a predetermined pressure on one side of said cylinder less than the'pressure supplied-from said pump.

Back blades for'snowplows are-employed to scrape the snow from the edges of the walls, garage doorsand the like. The back blades must be positioned firmly on the'ground and must also have a give in-the horizontal direction if the blade con= tacts-an uneven surface.

It'is desirableto raise and lowerth'e backbladesince it is notalways used. Considerable power is required to raise the blade; It is also desirable to apply pressure-to the blade when it is in the down position. However, if too much pressure is ap-' plied over and above the weight of the blade assembly, the

blade will wear out, or will have a tendency to raise the rear drive wheels of the vehicle off the ground thereby rendering the vehicle inoperative unless it has a four-wheel drive, and/or will create too much dragon the scraping operation.

I have now discovered a control system'for a back blade assembly in which a first predetermined pressure is supplied to the first pressurec'an be employed to hold theblade down in.

position.

By various aspects of this invention, one or'm'ore'of thefollowing or otherobjects, can be obtained.

It is an object of this invention to provide a novelback blade snowplow assembly for a truck.

It is a further object of this invention to provide aback blade assembly for a snowplow or the like wherein theblade is horizontally yieldable to compensate for normal ground protrusions.

It is a further object of this invention to provide'a-control system for'a back blade of a vehicle where a predetermined pressure is maintained on a blade to hold thesame against the ground, but which pressure is not sufficient to cause undue drag on the plowing operation, and/or is insufficient to cause. excessive wear on the blade, or is insufficient to raise rear wheels off the ground.

Other aspects, objects, and the several advantages of this invention are apparent to one skilled in the an from a study of this disclosure, the drawings, andtheapp'ende'dclaims.

According to the invention, there isprovided aback blade assembly for a vehicle. The assembly'comprisesa first support means adapted to be rotatably attached to the back of a vehi'-- cle. The first support means is rotatably attached to a scraping blade. A second support means is rotatably attached to the blade, but a spaced vertical distance, preferably below the attachme'nt of the first support means to the blade. The second support means is attached to the first support-means such that the bottom scraping surface of the blade will be yieldable in a horizontal direction in the event th'ata ground protrusion is hit by the blade. To this end, the second support means is rotatably attached to the first support means and is also reciprocatable with respect to the first support means.

Power means are also provided to raise and lower the blade. The-power means preferably are attached to the second sup port means.

Means are provided to yieldably maintain the blade in a vertical position.

According to one embodiment of the invention, the back blade is raised and lowered by a novel control system in'which the power or pressure employed in'fo'rcing the blade against the ground surface.

Theinvention will now be described withreference to the accompanying drawings in which:

FIG. 1 is a perspective view of a-novel back blade assembly as attached to the back portion of a truck;

FIG. 2-is a plan view of-the assembly shown in FIG. I;

FIG. 3. is a sectional view through lines III-Ill of FIG. 2;.

FIG. 4." is a-schematic view of the novel control system according tothe invention;

FIG. Sisa top view of a valve schematically shown'in'FIG. 4; 1

FIG. 6is a sideaview taken along lines VI-VI of FIG. 5;

FIG. 7'is a sectional view of the valve shown in FIG. S'taken along lines VIIVII of FIG. 6;-and

FIG. 8'is another sectional view of the valve shown'in FIGS. Sand 6 taken along lines-VlIl-VIII of FIG. 6.

Referring now to thedrawings and FIGS. I through 3. particularly, thereis shown a back blade assembly for a snowplow. Theback of a'truck 2 is provided with a supportbeam 4 having a supportingzbox'6'. Attached to the bottomportion of the-.supportingbox6 are support members 8'and 10 which are connected by a crossmember 12' to form a rigidH-shapedsupport; .Themembers '8 and 10 are attached at 16 and 30, respectively to a. scraper blade 14. Member 8 isattached through pin 18' and member-l0 is attached through pin 22; Members 8 and 'lflarerotatably attached to box 6. The cross member 12includes a central rod 13 as seenin FIG. 3.

Also rotatably attached to back blade 14 are second support members '26f-and 24'. The back blade is attached at 34 and 32 through pins 28 and 30 to second support members 26 and-24 respectively. The otherend'of secondary support members 24. and 26' are'attached to collar 38 and 36, respectively of cross member 12. The collars38" and 36 are rotatable about crossmember 12 on rod13. Support'members 24 and 26 extend through sleeves 37 and. 35 and are slidably engaged thereby. Sleeve'37 is fixed to collar 38 and sleeve, 35 is fixed to collar 36. The end portion of' supports 24 and 26 have attached thereto end caps 42'and 40; These end caps are biased against caps 40'and 44 through spring members 48 and 50, respectively. Support members 24 and 26 contain spring members 23 and 25" respectively, which are retained in place by caps 29.

Set screws (notshown) in .caps 29 fix their position on supportblade will yieldabout pins 18 and 22 due to the spring action of 48 and 50, and springs 23 and 25.

The bladecan beraised and lowered through a hydraulic cylinder152' supplied through hoses 60 and 64. The hydraulic cylinder'has-an extensible rod which is attached to collar 56 of crossmember 12. The. collar 56 is rotatable about crossmember 1'2. On the other end, the hydraulic cylinder is rotatably attached to the top portion of box 6. Thus, when the hydraulic cylinder 52 is actuated to extend rod 54, the blade 14 will be moved downwardly. Conversely, when the rod 54 is withdrawn into cylinder 52, the blade 14 will be raised.

The hydraulic cylinder is actuated through anovel control system shown in FIGS. 4 through 8. Referring now specifically to FIG. 4, a reservoir supplies fluid through 82, pump 84, line 86 to valve 88. The fluid pressure can pass through valve 88 to line 60 to one end of hydraulic cylinder 52 containing piston 62 which is attached to rod 54. Depending on the position of valve 88. the fluid can also pass through line 66 and.

back to reservoir 80 or to line 64 to the cylinder to cause the rod 54 to be retracted.

The valve 88 contains a first channel 68, a second channel 70, and a third channel 72. When the valve is in the neutral position, supply line 86 communicates with return line 66 via channel 70. When the valve is rotated in a clockwise direction, for example, line 86 communicates with line 60 to cause the piston 62 in the cylinder 52 to move to the left, as shown in FIG. 4. At the same time, line 64 will communicate with return line 66 to exhaust fluid from the left end of the cylinder.

When the valve is rotated in the counterclockwise direction, supply line 86 will be in communication with line 64, thereby forcing piston 62 to the right as shown in FIG. 4. At the same time, line 60 will be communicating with return line 66, whereby the fluid in the right side of the cylinder 52 will be exhausted.

According to the invention, a small bleed line 76 is provided in channel 68. This bleed line 76 communicates with exterior line 74 which communicates with return line 66. When the valve is rotated clockwise, so that supply line 86 communicates with line 60 through channel 68, a small portion of the fluid supplied will pass through line 76, line 74, and be returned through line 66. In this manner, the amount of pressure supplied to line 60 is less than that supplied by pump 84 to line 86. In the operation of the invention, this reduction in pressure is advantageous, as it permits a required amount of pressure to be supplied to the left end of the cylinder to raise the blade assembly and a lesser amount of pressure to be employed in lowering the blade assembly and holding the same against the ground when scraping. In this manner, excessive wear and excessive drag on the back blade is eliminated.

Reference is now made to FIGS. through 8, wherein there is shown an example of the valve schematically shown in FIG. 4. The valve contains sections 90, 92, and 94 suitably bolted together. Lines 60, 64, 66, and 86 are attached to section 94. As can be seen in FIG. 7, a bore 98 communicates with line 60. a bore 96 communicates with line 86, a bore 104 communicates with line 64, and bores 100 and 102 communicate with line 66.

A handle 106 is provided and attached to shaft 107 to actuate the valve to various positions. The valve is spring biased by wound spring 108, the ends of which bear against pin 110 on handle I06 and pin 110' on the top of the valve. In this manner the handle is biased in a central position and can be turned clockwise or counterclockwise against the spring ten- As can be seen in FIG. 8, the central portion 92 is annular in cross section and has positioned therein a core 1l2i Rod 107 is keyed to core 112 through pin 134 in channel 132. Vertical bore 136 communicates with channel 132 and with bore 96 of top plate 94. Vertical bore 138 communicates with channel 132 and with bore 100 of top plate 94. On the other hand, bore 102 communicates with annular space 128 which surrounds core 112. Bore 120 is connected to bore 122 through a diagonal bore .124. Bore 122 also has a laterally extending smaller channel 126 which communicates with the annular space 128.

Core 112 also has bore 114 which communicates with bore 116 through channel 118.

As shown in FIGS. 5 through 8, the valve is positioned at rest. In this position, fluid supplied through line 86 will pass through bore 96, bore 136, channel 132, bore 138, annular space 128. bores 100 and 102 to line 66 back to the reservoir. When the handle is moved against the spring tension clockwise, as shown in FIG. 5, the core member 112 will rotate so that bore 116 communicates with bore 100 and bore 114 communicates with bore 104. At the same time, bore 122 will be positioned over bore 98 and bore '120 will be positioned over bore 96. At this time, fluid supplied by pump 84 through line '86 will pass through bore 96, 120, 124, 98, and line 60 to cylinder 52. At the same time, the fluid in line 64 will be exhausted through bore 104, 114, 118, 116, 100, and line 66. Also, fluid pressure will bleed from port 122 through narrow channel 126 into annular space 128 and into port 102.'

through line 66, back to reservoir 80. In this mariner, the-pres sure supplied to line 60 will be less than that supplied by pump 86.

When the handle 106 is rotated counterclockwise, as shown in FIG. 5, bore 114 will be positioned over bore 96, bore 116 will be positioned over bore 104, bore 120 will be positioned over 98, and bore 122 will be positioned over bore 100. In this position, the fluid will pass from line 86 through bore 96, bore 114, 118, 116, 104, and into line 64, forcing piston 62 to the right, as shown in FIG. 4. At the same time, fluid in line 60 will pass through bores 98, 120, 124, 126, 138, through line 66 to reservoir 80.

The bottom plate member of the valve shown in FIGS. 5 through 8, is substantially solid in cross section, and merely blocks off the annular space 128 and the bottom'end of core Suitable seals (not shown) are provided between top plate 94 and shaft 107, and between top plate 104, part 92 and bottom plate 90.

In constructing the valve shown in FIGS. 5 through 8, a plurality of vertical screws are employed in fastening the three sections of the valve together. However, for purposes of simplicity in describing the invention, these bolts have not been shown.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, the drawings, and the the claims to the invention without departing from the spirit thereof.

Iclaim:

l. A blade assembly for mounting on the rear end of a truck and the like comprising:

A. a scraper blade, a frame member;

B. a first support means rotatably attached to said frame member at one end and rotatably attached to said scraper blade at another end;

C. a rigid second support means rotatably attached at one end to said scraper blade a spaced vertical distance from said first support means;

D. means resiliently mounting said second support means to said first support means a spaced distance from said scraper blade such that said scraper blade is held substantially vertical but is yieldable at the bottom portion thereof in a horizontal direction; and

E. power means rotatably attached to said frame member, said power means including a reciprocable rod rotatably attached to said first support means.

2. A back blade assembly according to claim 1, wherein said attachment means for said power means includes a means for rotatably attaching said rod to said support means.

3. A back blade assembly according to claim 1, wherein said first support means comprises two rods rotatably attached to said blade and a crossmember connecting said two rods, said power means rod is rotatably attached to said crossmember, and said second support means is rotatably attached to said crossmember 4. A back blade assembly according to claim I, wherein said power means is a hydraulic cylinder with a piston attached to said rod.

5. A back blade assembly according to claim 1, wherein said second support means is rotatably and reciprocably attached to said first support means and there is provided a biasing means between said first and second support means to provide said resilient mounting.

6. A truck having attached thereto the blade assembly of claim 1, wherein said frame member is rigidly secured to the back portion of said truck.

7. A blade assembly according to claim 1 wherein said resilient mounting means includes a sleeve pivotably mounted on said first support means, and said second support means includes a shaft slidable in said sleeve.

8. A blade assembly according to claim 7 wherein said resilient mounting means further comprises biasing means between said shaft and said sleeve to resiliently maintain said shaft in a given position within said sleeve. 

